Multilamellar Thermoresponsive Emulsions Stabilized with Biocompatible Semicrystalline Block Copolymers.

We demonstrate specific interface-templated crystallization behavior of biocompatible amphiphilic poly(ethylene oxide)-b-poly(ε-caprolactone) (PEO-b-PCL) block copolymers enabling triggered shaping of the curvature of the oil/water interface and controlled phase inversion, including the formation of stable multiple emulsions. Water-born anisotropic micelles of PEO-b-PCL block copolymers self-assemble at the oil-water interface in a multilayer form and undergo conformational rearrangements into unique semicrystalline multilamellar shells, for which curvature (type of emulsion) can be tuned by the molecular architecture (volume fractions of the blocks) and/or by the temperature. The latter trigger affects both the solubility of the PEO block in water and the semicrystalline state of the PCL block. Remarkably, multilamellar semicrystalline shells provide both long-term stability and enhanced barrier properties of toluene-water emulsions, as well as the fast change of the bending, leading to thermo-induced phase inversion. These findings signify the development of novel practical mechanisms for controlled triggered encapsulation and release systems.

Fabrication of highly porous scaffolds for tissue engineering based on star-shaped functional poly(ε-caprolactone).

The potential of novel functional star-shaped poly(ε-caprolactone)s of controlled molecular weight and low molecular weight distribution bearing acrylate end groups as material for biomedical applications was demonstrated in this study. The polymers were functionalized via Michael-type addition of amino acid esters containing amino or thiol groups showing the potential for immobilization of biomolecules. Furthermore, scaffolds of different geometries were prepared by uniaxial freezing of polymer solutions followed by freeze drying. Different solvents and polymer concentrations were investigated, resulting in scaffolds with porosities between 76 and 96%. Mechanical properties of the scaffolds were investigated and the morphology was determined via scanning electron microscopy. Scaffolds with interconnected channels were prepared using benzene, 1,2-dichloroethane or dioxane as solvent. The tubular longitudinal pores in honeycomb arrangement extend throughout the full extent of the scaffolds (typical pore sizes: 20-100 µm).